This invention relates to the field of centrifugal rotors and, more particularly, is related to the field of swinging carrier rotors or swinging bucket rotors.
With presently used swinging carrier rotors, the carrier generally has a rectangular shape designed to receive particular types of test tube racks, such as those that may be used in a radioimmunoassay instrument. Another type of swinging carrier rotor is a swinging bucket rotor where the bucket either contains a large specimen to be centrifugated or may contain an adapter to hold a plurality of smaller test tubes for subjection to centrifugation.
In any swinging carrier type centrifuge rotor the sample receptacles typically assume a vertical or close to vertical orientation when the rotor is at rest. In other words, the test tubes are in many cases generally parallel to the rotational axis of the rotor when the rotor is at rest, although in some cases the longitudinal axis of the test tubes may be at a slight acute angle to the rotational axis of the rotor. When the rotor reaches operational speeds during centrifugation, the swinging carrier or bucket will assume a second orientation, resulting in the longitudinal axis of each test tube generally assuming a perpendicular orientation with respect to the rotational axis of the rotor. The support base on which these test tube samples or test tubes rest generally assumes a parallel orientation with respect to the spin axis of the rotor when the rotor is at operational speed.
It is critical to successful centrifugation that the test tubes carrying the samples are as perpendicular as possible to the rotational axis of the rotor during centrifugation. In present configurations of swinging type centrifuge rotors there is friction at the interface of the pivotal carrier and the rotor frame which prevents the carrier from assuming its proper orientation with respect to the spin axis during the operational speed of the rotor. This would not only result in a possible unbalanced condition in the rotor, but also cause some samples within the carrier to be subjected to a different centrifugal field than others.